Embodiments of the present inventive concept relate to use of nonvolatile memory devices, and more particularly, to a method of controlling data writing of a nonvolatile memory device and a memory controller having a wear-leveling controlling function
Recently, magnetic random access memory (MRAM) has been studied as memory able to replace not only flash memory for data storage, but also dynamic random access memory (DRAM) for working storage. To replace DRAM with MRAM, memory endurance has to be increased.
In flash memory, wear-leveling techniques are used for equalizing the number of erasures of memory blocks. However, when block size increases significantly due to high capacity of the memory, an endurance difference occurs between word lines in the same memory block. This is because when block size becomes very large, a merge operation may be performed before memory cells connected to word lines in each block are all written. Consequently, all the memory cells connected to word lines in a memory block are not evenly used. For instance, word lines located closer to a memory area in which a write operation of the memory block begins are used relatively often, and word lines located further away from the memory area in which the write operation begins are less frequently used. Thus, wear-levels between word lines in the memory block may differ substantially.